Diaphragm pumps include a chamber that is divided by a piston and diaphragm so as to provide a first sub-chamber that receives a working fluid (liquid or gas) under pressure, and a second sub-chamber that receives a fluid being pumped. Usually the working fluid is compressed air. The working fluid under pressure is delivered to the first sub-chamber to cause reciprocation of the piston and diaphragm to vary the volume of the second sub-chamber, and thereby pump the fluid to be pumped by the assembly. These diaphragm pumps have an inlet and an outlet that communicate with the second sub-chamber via one-way valves so that the fluid being pumped passes in a predetermined direction through the pump assembly. A first manifold joins the inlet with the second sub-chamber while a second manifold joins the second sub-chamber with the outlet.
The above pump assemblies include a first body part providing the second sub-chamber, and a second body part providing the first sub-chamber. The first part provides for mounting of the one-way valves, while the diaphragm is held in position by being secured between the first and second body parts.
A disadvantage of the above described pump assemblies is that first part is generally an assembly and therefore requires gaskets, seals and securing means for its assembly. The disadvantage in that the construction is complex and time in respect of construction. This adds considerably to the cost of the pump assembly.
A further disadvantage of the above pump assemblies is resistance to flow of the pump fluid through the pump assembly.
A further disadvantage of the above assemblies is at least one of the pump parts have embedded in them bolts that protrude and are engaged by the other pump part. The use of these bolts inhibits efficient moulding of the pump parts.
Described in U.S. Pat. Nos. 5,564,911 and 6,834,678, and International Patent Applications PCT/AU2009/000199, PCT/AU2011/000226 and PCT/AU2014/000151 are pump assemblies relating to the present invention.